With a rapid development of display technology, touch panels have been gradually popularized in people's lives. At present, the touch panels may be divided into the following types according to the working principle: a resistive type, a capacitive type, an infrared type, a surface acoustic wave type, an electromagnetic type, a dispersive signal type, and an inhibited total internal reflection optical sensing type, etc. Among these, a capacitive touch panel has been sought after as a new favorite in the industry because of its special touch principle, advantages such as high sensitivity, long lifespan, and high transmission.
For a capacitive touch panel, OGS (One Glass Solution, OGS) touch panel has occupied a certain share in the high-end market. The OGS touch panel comprises a four-layer structure, i.e. a metallic layer, an insulating layer, a transparent electrode layer, and a passivation protective layer formed in turn on a glass substrate. In a producing process of the OGS touch panel, an edge enhancement process is a crucial factor to determine the product yield. The edge enhancement process refers to: forming a protective acid-proof ink coating on two surfaces of the touch panel, immersing the touch panel formed with the acid-proof ink coating into an acid substance (e.g. hydrofluoric acid), and corroding away burrs generated when a glass substrate is cut, so as to enhance edge strength of the touch panel.
However, because a sealing between the acid-proof ink coating and a periphery region of the touch panel is relatively poor, when the OGS touch panel is edge-enhanced, the acid substance will easily enter an interior region from the peripheral region of the touch panel, resulting in corroding and damaging interior structures (e.g. a transparent electrode), and affecting the product yield.